I have a friend who is a Materials Science Technologist and specializes in injection molded plastics. So... basically the same thing that's in computer cases (even though he doesn't deal with computer cases). I grilled him at length on this topic, and he insisted that the brittleness with age (and UV light) is expected and irreversible. Basically, the plastic softeners are off-gassing, and there's no way to put them back in. I'm still hoping for a happier second opinion, though I'm not holding my breath. In my experience, brittleness varies wildly and goes from "no big deal" to "crumbles if you blow at it", even for otherwise identical machines. I recently acquired a Japanese Ultra 1 clone, and the back was smashed in shipping, and crumbled into a thousand pieces not even large enough to glue back together. Luckily the front only had a single crack that could be glued back together. On Fri, Aug 28, 2020 at 9:38 AM Tom Hunter via cctalk < cctalk at classiccmp.org> wrote: CDROM units

On 9/2/20 12:02 PM, Rico Pajarola via cctalk wrote: > I have a friend who is a Materials Science Technologist and > specializes in > injection molded plastics. So... basically the same thing that's in > computer cases (even though he doesn't deal with computer cases). I > grilled > him at length on this topic, and he insisted that the brittleness > with age > (and UV light) is expected and irreversible. Basically, the plastic > softeners are off-gassing, and there's no way to put them back in. > > I'm still hoping for a happier second opinion, though I'm not > holding my > breath. >

It's a very well-known problem among the museum conservation crowd --and with no practical solution. For a discussion, WikiPedia is pretty informative:

I have a friend who is a Materials Science Technologist and specializes in injection molded plastics. So... basically the same thing that's in computer cases (even though he doesn't deal with computer cases). I grilled him at length on this topic, and he insisted that the brittleness with age (and UV light) is expected and irreversible. Basically, the plastic softeners are off-gassing, and there's no way to put them back in. I'm still hoping for a happier second opinion, though I'm not holding my breath. In my experience, brittleness varies wildly and goes from "no big deal" to "crumbles if you blow at it", even for otherwise identical machines. I recently acquired a Japanese Ultra 1 clone, and the back was smashed in shipping, and crumbled into a thousand pieces not even large enough to glue back together. Luckily the front only had a single crack that could be glued back together. On Fri, Aug 28, 2020 at 9:38 AM Tom Hunter via cctalk <cctalk at classiccmp.org> wrote: > Today I was working on a very nice 1995 vintage SPARCstation LX with CDROM > and QIC-150 tape drive (3 lunchbox type units). I was trying to install a > newer version of NetBSD on it than was already installed. The stack of 3 > units was stored in a museum grade glass display cabinet. Sadly all 3 units > have a small degree of yellowing but more importantly the plastic cases > have become very brittle and bits just break off with minimal mechanical > strain. > > Is there any process to reverse the brittleness which could be used to > preserve the cases? > > Thanks > Tom Hunter >